Here I'll help:
1. Both FB and I are suggesting that you are running way too large of a tube and tire in a narrow rim. Perhaps you need to bring it down to 700 x 28c?
2. FB is suggesting going presta...narrows the base of the tube a little stem construction wise so the stem base is flush against the rim - not sitting on the side ramps.
...as he pointed out - it the stem is sitting high - the tube before and after can bulge into the gap under and BAM - blown tube.
Too make a long story short:
It's a compatibility thing - narrow rim + large tube + large tire - it's not working out as-is.
=8-)
__________________
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
Last edited by mrrabbit; 09-08-12 at 01:55 PM.